/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @author Vladimir N. Molotkov, Alexander Y. Kleymenov
 */

package org.apache.harmony.security.x509;

import java.io.IOException;
import java.math.BigInteger;

import org.apache.harmony.security.asn1.ASN1Implicit;
import org.apache.harmony.security.asn1.ASN1Integer;
import org.apache.harmony.security.asn1.ASN1Sequence;
import org.apache.harmony.security.asn1.ASN1Type;
import org.apache.harmony.security.asn1.BerInputStream;

/**
 * The class encapsulates the ASN.1 DER encoding/decoding work with
 * PolicyConstraints structure which is a part of X.509 certificate (as
 * specified in RFC 3280 - Internet X.509 Public Key Infrastructure. Certificate
 * and Certificate Revocation List (CRL) Profile.
 * http://www.ietf.org/rfc/rfc3280.txt):
 * 
 * <pre>
 * 
 *  PolicyConstraints ::= SEQUENCE {
 *       requireExplicitPolicy           [0] SkipCerts OPTIONAL,
 *       inhibitPolicyMapping            [1] SkipCerts OPTIONAL }
 * 
 *  SkipCerts ::= INTEGER (0..MAX)
 * 
 * </pre>
 * 
 * TODO: This class is not fully implemented.
 * 
 * @see org.apache.harmony.security.x509.GeneralSubtree
 * @see org.apache.harmony.security.x509.GeneralName
 */
public class PolicyConstraints extends ExtensionValue {

	// the value of requireExplicitPolicy field of the structure
	private final BigInteger requireExplicitPolicy;
	// the value of inhibitPolicyMapping field of the structure
	private final BigInteger inhibitPolicyMapping;
	// the ASN.1 encoded form of PolicyConstraints;
	private byte[] encoding;

	/**
	 * X.509 PolicyConstraints encoder/decoder.
	 */
	public static final ASN1Sequence ASN1 = new ASN1Sequence(new ASN1Type[] {
			new ASN1Implicit(0, ASN1Integer.getInstance()),
			new ASN1Implicit(1, ASN1Integer.getInstance()) }) {
		{
			setOptional(0);
			setOptional(1);
		}

		@Override
		protected Object getDecodedObject(BerInputStream in) {
			final Object[] values = (Object[]) in.content;
			BigInteger requireExplicitPolicy = null;
			BigInteger inhibitPolicyMapping = null;
			if (values[0] != null) {
				requireExplicitPolicy = new BigInteger((byte[]) values[0]);
			}
			if (values[1] != null) {
				inhibitPolicyMapping = new BigInteger((byte[]) values[1]);
			}
			return new PolicyConstraints(requireExplicitPolicy,
					inhibitPolicyMapping, in.getEncoded());
		}

		@Override
		protected void getValues(Object object, Object[] values) {

			final PolicyConstraints pc = (PolicyConstraints) object;

			values[0] = pc.requireExplicitPolicy.toByteArray();
			values[1] = pc.inhibitPolicyMapping.toByteArray();
		}
	};

	/**
	 * TODO
	 */
	public PolicyConstraints() {
		this(null, null);
	}

	/**
	 * TODO
	 * 
	 * @param requireExplicitPolicy
	 *            : GeneralSubtrees
	 * @param inhibitPolicyMapping
	 *            : GeneralSubtrees
	 */
	public PolicyConstraints(BigInteger requireExplicitPolicy,
			BigInteger inhibitPolicyMapping) {
		this.requireExplicitPolicy = requireExplicitPolicy;
		this.inhibitPolicyMapping = inhibitPolicyMapping;
	}

	//
	// TODO
	// @param requireExplicitPolicy: GeneralSubtrees
	// @param inhibitPolicyMapping: GeneralSubtrees
	// @param encoding: byte[]
	//
	private PolicyConstraints(BigInteger requireExplicitPolicy,
			BigInteger inhibitPolicyMapping, byte[] encoding) {
		this(requireExplicitPolicy, inhibitPolicyMapping);
		this.encoding = encoding;
	}

	public PolicyConstraints(byte[] encoding) throws IOException {
		super(encoding);
		final PolicyConstraints pc = (PolicyConstraints) ASN1.decode(encoding);
		requireExplicitPolicy = pc.requireExplicitPolicy;
		inhibitPolicyMapping = pc.inhibitPolicyMapping;
	}

	/**
	 * TODO
	 * 
	 * @param requireExplicitPolicy
	 *            : GeneralSubtrees
	 * @param inhibitPolicyMapping
	 *            : GeneralSubtrees
	 */
	public PolicyConstraints(int requireExplicitPolicy, int inhibitPolicyMapping) {
		this.requireExplicitPolicy = BigInteger.valueOf(requireExplicitPolicy);
		this.inhibitPolicyMapping = BigInteger.valueOf(inhibitPolicyMapping);
	}

	/**
	 * Places the string representation of extension value into the StringBuffer
	 * object.
	 */
	@Override
	public void dumpValue(StringBuffer buffer, String prefix) {
		buffer.append(prefix).append("PolicyConstraints: [\n"); //$NON-NLS-1$
		if (requireExplicitPolicy != null) {
			buffer.append(prefix).append("  requireExplicitPolicy: ") //$NON-NLS-1$
					.append(requireExplicitPolicy).append('\n');
		}
		if (inhibitPolicyMapping != null) {
			buffer.append(prefix).append("  inhibitPolicyMapping: ") //$NON-NLS-1$
					.append(inhibitPolicyMapping).append('\n');
		}
		buffer.append(prefix).append("]\n"); //$NON-NLS-1$
	}

	/**
	 * Returns ASN.1 encoded form of this X.509 PolicyConstraints value.
	 * 
	 * @return a byte array containing ASN.1 encode form.
	 */
	@Override
	public byte[] getEncoded() {
		if (encoding == null) {
			encoding = ASN1.encode(this);
		}
		return encoding;
	}
}
